發(fā)布時間：2018-06-22 21:44

  本文選題：尿素氯化銨 + 密度分選法��； 參考：《山西師范大學》2017年碩士論文

【摘要】：我們研究小組發(fā)現(xiàn)并提出了一種新的、簡單的、在工業(yè)規(guī)模上合成尿素氯化銨(U-AC)共晶的方法-固相微孔道法。本文主要研究了專門針對固相法生長尿素氯化銨共晶的一種提純工藝,旨在分離、提純得到純凈的U-AC,便于以后的研究以及性質(zhì)測試。U-AC的分離提純工藝由一系列操作構(gòu)成,主要分為兩個部分:第一部分通過重結(jié)晶得到尿素氯化銨的粗產(chǎn)物;第二部分利用密度分選法對重結(jié)晶產(chǎn)物進一步分離提純。最后,將此提純工藝在工業(yè)規(guī)模上大試。首先,由于尿素氯化銨共晶是生長在復合肥顆粒中的,通過風選法將尿素氯化銨共晶從復合肥顆粒中初步分離出來,然后通過溶解、過濾、氨基酸輔助重結(jié)晶得到尿素氯化銨粗產(chǎn)物。其中,通過比較添加抑制劑氨基酸前后,尿素氯化銨的重結(jié)晶產(chǎn)率,選出了對尿素氯化銨分解具有抑制作用的氨基酸,并對抑制劑的濃度、重結(jié)晶的溫度進行了選擇。最后分析了L-半胱氨酸抑制尿素氯化銨分解的機理。通過測試,L-半胱氨酸輔助U-AC重結(jié)晶與直接重結(jié)晶U-AC相比,產(chǎn)率從52.41%提升到了78.26%,具有顯著的效果。其次,由于尿素氯化銨易于分解,重結(jié)晶產(chǎn)物仍然是一個混合物其中含有尿素、氯化銨等雜質(zhì)。通過密度分離法,以苯和四氯化碳為分選介質(zhì)依次將尿素和氯化銨除去。密度分選法需要兩次,第一次分選苯與四氯化碳的體積比為1:2,此時,尿素漂浮在介質(zhì)表面,氯化銨與尿素氯化銨沉在下層。將第一次的下層的物質(zhì)再進行第二次分選以達到除去氯化銨的目的,此時苯與四氯化碳的體積為1:4.5,在此比例的介質(zhì)中,尿素氯化銨漂浮在介質(zhì)的表面,而氯化銨沉在介質(zhì)的底部。每次分離后可以通過過濾的方法得到目標物質(zhì)。最后,得到目標化合物經(jīng)XRD鑒定,氯和氮含量的測定與標準值對比。結(jié)果表明,U-AC純度大大地提高。最后,將提純方法應用于實際大規(guī)模提純過程中,并對尿素氯化銨的性質(zhì)進行了研究,發(fā)現(xiàn)尿素氯化銨溶液具有耐火性,可以用作耐火材料。
[Abstract]:Our team found and proposed a new and simple method for the synthesis of urea-ammonium chloride (U-AC) eutectic on an industrial scale-solid phase micropore method. In this paper, a purification process for the growth of urea ammonium chloride eutectic by solid phase method is studied. The purpose of this process is to separate and purify the pure U-AC, which is easy to be studied in the future and the separation and purification process of .U-AC is composed of a series of operations. It is mainly divided into two parts: in the first part, the crude products of urea ammonium chloride are obtained by recrystallization; in the second part, the recrystallization products are further separated and purified by density sorting method. Finally, the purification process was tested on industrial scale. First of all, because urea ammonium chloride eutectic is grown in compound fertilizer particles, urea ammonium chloride eutectic is initially separated from compound fertilizer particles by wind separation method, and then dissolved and filtered. Amino acid assisted recrystallization gave urea ammonium chloride crude product. By comparing the recrystallization yield of urea ammonium chloride before and after the addition of inhibitor amino acids, the amino acids which can inhibit the decomposition of urea ammonium chloride were selected, and the concentration of the inhibitor and the recrystallization temperature were selected. Finally, the mechanism of L-cysteine inhibiting the decomposition of urea ammonium chloride was analyzed. Compared with direct recrystallization, the yield of L-cysteine assisted U-AC recrystallization increased from 52.41% to 78.26%. Secondly, because urea ammonium chloride is easy to decompose, the recrystallization product is still a mixture containing urea, ammonium chloride and other impurities. Using benzene and carbon tetrachloride as separation medium, urea and ammonium chloride were removed by density separation method. The volume ratio of benzene to carbon tetrachloride is 1: 2 for the first time, when urea floats on the surface of the medium, ammonium chloride and urea ammonium chloride precipitate in the lower layer. A second separation of substances from the first lower layer to remove ammonium chloride is achieved, when the volume of benzene and carbon tetrachloride is 1: 4.5. In this proportion, ammonium urea chloride floats on the surface of the medium. Ammonium chloride is deposited at the bottom of the medium. The target substance can be obtained by filtration after each separation. Finally, the target compound was identified by XRD, and the content of chlorine and nitrogen was compared with the standard value. The results show that the purity of U-AC is greatly improved. Finally, the purification method was applied to the large-scale purification process, and the properties of urea ammonium chloride were studied. It was found that the urea ammonium chloride solution had fire resistance and could be used as refractories.
【學位授予單位】：山西師范大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：TQ441.41

【參考文獻】

相關期刊論文 前10條

1 江曉靜;;單晶培養(yǎng)的方法和影響因素[J];化工管理;2013年12期

2 邱言鋒;李明偉;程e，

本文編號：2054320